P-38 LIGHTNING Redux

“The P-38 was very unusual. Imagine what I felt when first climbing on board that airplane. Sitting on that tricycle landing gear, it was very high off the ground. There was a stepladder that dropped out of the tail end of the fuselage pod, and you took two steps up this ladder and the third step was onto the wing next to the canopy. … It was a good sized airplane. In comparison the P-39 was a midget, almost like a toy.

It was very fast and had good firepower. That gave a lot of people false confidence when they first went to P-38s. Their limitations on tactics were the same as those we were accustomed to in the P-40s, but even more so. You did not go looking for a close-in dogfight with an Oscar or Zero. Japanese planes were quicker … at slow speed. But new pilots did not always realize the consequences. If the speed bled off a P-38, which happened very easily, it could be in serious trouble against a Japanese fighter. Many of our men found out the hard way, particularly when we first started receiving the P-38s.”

Robert DeHaven, a P-38, 14-kill ace with the 49th Fighter Group

The Lockheed P-38 Lightning was a formidable and unique fighter. With its distinctive twin booms each containing an engine and a single, central nacelle containing the cockpit and armament. Originally, due to be called the Atlanta, it was a failed RAF order for 143 aircraft that led to the Lightning name. As well as interception, the P-38 was used in night fighting, photo reconnaissance, radar and visual pathfinding for bombers and with drops tanks fitted as a long-range escort fighter.

The P-38 came about in response to a United States Army Air Corps specification in February 1937 known as Circular Proposal X-608. It was based on performance goals set by First Lieutenant Benjamin S. Kelsey and First Lieutenant Gordon P. Saville. The specification was for a twin-engine, high-altitude “interceptor” having “the tactical mission of interception and attack of hostile aircraft at high altitude.

  1. A speed of at least 360 mph at 20,000 feet. (The desired maximum speed was 400 mph).
  2. Climb to 20,000 feet in six minutes or less.
  3. Fuel for one hour at operating speed.
  4. Armament was to be designed around a Rapid-fire cannon, as destruction of enemy bombers was considered the primary function.

At the time these were the toughest proposals the United States Army Air Corps had set. The proposal also required a liquid-cooled Allison V-1710 engines with turbo-superchargers and gave extra points for tricycle landing gear.

Lockheed set to work on meeting the specification led by the famous Kelly Johnson who would go on to later design the U-2 and SR-71 spy planes. Kelly considered a range of design proposals including having two engines back to back with a push pull propeller arrangement. The final design was contemporary for fighter design at the time and in some respects ahead of its time.

The XP-38 gondola mockup with armament, concentrated in the nose of the aircraft and was designed to mount two .50-caliber M2 Browning machine guns, two .30-caliber Browning’s, and a T1 Army Ordnance 23 mm autocannon with a rotary magazine In the YP-38s, a larger John Browning-designed, Colt-made M9 1.46 in autocannon with 15 rounds replaced the T1. Although the M9 did not perform reliably in flight. Further armament experiments from March to June 1941 resulted in the P-38E combat configuration of four M2 Browning machine guns, and one Hispano .79 in autocannon with 150 rounds. Having all the armament was a move away from almost all other U.S aircraft at the time. A P-38 could reliably hit targets at any range up to 1,000yd.

The Lockheed design also incorporated tricycle undercarriage and a bubble canopy with two 1,000hp turbo-supercharged 12-cylinder Allison V-1710 engines fitted with counter-rotating propellers to eliminate the effect of engine torque which was put into practice by engines that had engine crankshafts operating in opposite directions. Another new design feature was the use of stainless steel and flush riveted aluminum skin which along with its twin engines helped it become the first fighter to pass the 400-mph mark. The YP-38 won the competition on 23 June 1937 and a prototype XP-38 although the money awarded for the prototype did not cover the prototypes eventual cost which was nearly five times the amount awarded to build the prototype.

Construction on the XP-38 began in July 1938 and the XP-38 made its first flight on 27 January 1939. However, on 11 February the prototype crashed just short of Mitchel Field runway in Hempstead, New York due to carburetor icing. The XP-38 had proved itself enough in is few short number of flights for the USAAC to order 13 prototypes now designated s YP – the Y being for prototype and the X for experimental. Initial production faced delays due to the mass production techniques required making them substantially different in construction from the XP-38. Lockheed’s works also needed to be expanded to accommodate production.

The first YP-38 was not completed until September 1940, with its maiden flight on 17 September. The final YP-38 being delivered to the USACC in June 1942. The YP-38 was actually lighter and the rotation of the propellers changed from inward to outward to improve stability as a gun platform. During test flights wat was initially believed to be tail flutter was found. The problem was that as the aircraft approached Mach 0.68, especially in a dive the YP-38s tail would start to shake violently and the nose pull downward making any dive even steeper. Once in the dive the aircraft would enter a high-speed compressibility stall. This was characterized by the controls locking up and the pilot being unable to pull out. In denser air there was a small chance the pilot would be able to pull out of the dive. In once such instance the pilot a Major Signa Gilkey managed to recover gradually using elevator trim. This issue was of a concern to Lockheed, but they also had the pressure of fulfilling the current order of aircraft. It was not until November 1941 that the engineering team had time to start tackling the problem. Several different solutions were tried including spring-loaded servo tabs on the elevator trailing edge that would give almost a power assistance to the controls once yoke forces rose to over 30 pounds. This however failed and an YP-38 and its pilot lost after a high G pull-out and the tail unit failing. The USAAC were positive it was caused by flutter and ordered the Lockheed design team to look at the tail. Flutter at the time, was a common issue with tails that were too flexible. However, the YP-38s tail was made from a rigid aluminum construction as opposed to the usual fabric construction common at the time. Lockheed skinned one tail with 63% thicker aluminum, but this did not solve the problem. Extra external masses were also tried but to no avail. Although these external masses were added to every new P-38 coming off the production line.

Finally, after tests, in a Mach 0.75 wind tunnel the compressibility problem was revealed to be the center of lift moving back toward the tail when in high-speed airflow. The problem was solved by changing the geometry of the wing’s underside when diving. This was achieved with quick acting dive flaps installed outboard of the engine nacelles. They extended downward 35° in 1.5 seconds. The flaps did not act as a speed brake; they affected the center of pressure distribution in a way that retained the wing’s lift. In February 1943 Lockheed’s test pilots proved this to be a successful solution. A kit was also designed so that the flaps could be retrofitted to existing P-38s. The flaps were incorporated into production line in June 1944 on the last 210 P-38Js. In the end, only the final 50% of all P-38s produced had the flaps factory fitted.

Johnson later recalled: “I broke an ulcer over compressibility on the P-38 because we flew into a speed range where no one had ever been before, and we had difficulty convincing people that it wasn’t the funny-looking airplane itself, but a fundamental physical problem. We found out what happened when the Lightning shed its tail and we worked during the whole war to get 15 more mph of speed out of the P-38. We saw compressibility as a brick wall for a long time. Then we learned how to get through it.”

Another issue found with the P-38 was it tendency to violently Yaw if it had an engine failure at takeoff. This was due to its unique design feature of outwardly rotating propellers which if failed caused a sudden drag to be induced yawing the nose and rolling the wingtip down on the side of the dead engine. If the pilot simply increased power to the good engine this made the situation worse and the P-38 would flip over. This issue was overcome by reducing power on the good engine feathering the prop on the failed engine and increasing thrust again on the good engine.

The first unit to receive P-38s was the 1st Fighter Group. After the attack on Pearl Harbor, the unit joined the 14th Pursuit Group in San Diego to provide West Coast defense. The first Lightning to see active service was a P-38E in which the guns were replaced by four K17 cameras. They joined the 8th Photographic Squadron out of Australia on 4 April 1942.

Three P-38E F-4s were operated by the Royal Australian Air Force in this theater for a short period beginning in September 1942.

On 29 May 1942, 25 P-38s began operating in the Aleutian Islands in Alaska. The fighter’s long range made it well-suited to the campaign over the almost 1,200 mi –long island chain, and it would be flown there for the rest of the war.

After the Battle of Midway, the USAAF began redeploying fighter groups to Britain as part of Operation Bolero, and Lightnings of the 1st Fighter Group were flown across the Atlantic via Iceland. On 14 August 1942, Second Lieutenant Elza Shahan of the 27th Fighter Squadron, and Second Lieutenant Joseph Shaffer of the 33rd Squadron operating out of Iceland shot down a Focke-Wulf Fw 200 Condor over the Atlantic. Shahan in his P-38F downed the Condor; Shaffer, flying either a P-40C or a P-39, had already set an engine on fire. This was the first Luftwaffe aircraft destroyed by the USAAF.

After 347 sorties with no enemy contact, the 1st, 14th and 82nd Fighter Groups were transferred to the 12th Air Force in North Africa as part of the force being built up for Operation Torch. On 19 November 1942, Lightning’s escorted a group of B-17 Flying Fortress bombers on a raid over Tunis. The P-38 remained active in the Mediterranean for the rest of the war. It was in this theatre that the P-38 suffered its heaviest losses in the air. On 25 August 1943, 13 P-38s were shot down in a single sortie by Bf 109s without achieving a single kill. On 2 September 10 P-38s were shot down, in return for a single kill. Kurt Bühligen, a German pilot, later said “The P-38 fighter along with the B-24 were easy to burn. Once in Africa we were a flight of six and met eight P-38s and shot down seven.” Experiences over Germany had shown a need for long-range escort fighters to protect the Eighth Air Force’s heavy bomber operations. The P-38Hs of the 55th Fighter Group were transferred to the Eighth in England in September 1943, and were joined by the 20th, 364th and 479th Fighter Groups soon after. P-38s soon joined Spitfires in escorting the early Fortress raids over Europe.

A little-known role of the P-38 in the European theatre was that of fighter-bomber during the invasion of Normandy and the Allied advance across France into Germany. The 370th participated in ground attack missions across Europe until February 1945 when the unit changed over to the P-51 Mustang.

After some disastrous raids in 1944 with B-17s escorted by P-38s and Republic P-47 Thunderbolts, Jimmy Doolittle, then head of the U.S. Eighth Air Force, went to the Royal Aircraft Establishment (RAE), Farnborough, asking for an evaluation of the various American fighters. Fleet Air Arm Captain and test pilot Eric Brown stated, “We had found out that the Bf109 and the Fw190 could fight up to a Mach of 0.75, three-quarters the speed of sound. We checked the Lightning and it couldn’t fly in combat faster than 0.68. So it was useless. We told Doolittle that all it was good for was photo-reconnaissance and had to be withdrawn from escort duties. And the funny thing is that the Americans had great difficulty understanding this because the Lightning had the two top aces in the Far East.”

However, the P-38 found itself most extensively used with success in the Pacific theatre, where it proved ideally suited, combining excellent performance with very long range, and had the added reliability of two engines for long missions over water. The P-38 was used in a variety of roles, especially escorting bombers at altitudes between 18 and 25,000ft. The P-38 was credited with destroying more Japanese aircraft than any other USAAF fighter. Whilst the P-38 could not out-turn the A6M Zero and most other Japanese fighters when flying below 200 mph, its superior speed coupled with a good rate of climb meant that it could utilize energy tactics, making multiple high-speed passes at its target. Also, its focused firepower was even more deadly to lightly armored Japanese warplanes than to the Germans’. The concentrated, parallel stream of bullets allowed aerial victory at much longer distances than fighters carrying wing guns.

The end of the war left the USAAF with thousands of P-38s rendered obsolete by the jet age. The last P-38s in service with the United States Air Force were retired in 1949. A total of 100 late-model P-38L and F-5 Lightning’s were acquired by Italy through an agreement dated April 1946. Delivered, after refurbishing, at the rate of one per month, they finally were all sent to the AMI by 1952. The Lightning’s served in 4 Stormo and other units including 3 Stormo, flying reconnaissance over the Balkans, ground attack, naval cooperation and air superiority missions. Due to unfamiliarity in operating heavy fighters, old engines, and pilot errors, a large number of P-38s were lost in at least 30 accidents, many of them fatal. Despite this, many Italian pilots liked the P-38 because of its excellent visibility on the ground and stability on takeoff. The Italian P-38s were phased out in 1956; none survived the inevitable scrapyard.

Surplus P-38s were also used by other foreign air forces with 12 sold to Honduras and 15 retained by China. Six F-5s and two unarmed black two-seater P-38s were operated by the Dominican Air Force based in San Isidro Airbase, Dominican Republic in 1947. The majority of wartime Lightning’s present in the continental U.S. at the end of the war were put up for sale for US$1,200 apiece; the rest were scrapped. P-38s in distant theatres of war were bulldozed into piles and abandoned or scrapped; very few avoided that fate. This brought the end to a unique and legendary fighter, it was not without its issues and overshadowed by the P-51 but was without a doubt a great American warbird.

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